JP2008276413A - Setting method for security to storage device, and computer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forbidding writing in an optical disk drive connected to a computer. <P>SOLUTION: In this method, a BIOS confirms presence/absence of a security function of the optical disk drive (S311). When the optical disk drive has the security function, the BIOS sends a command to make the optical disk drive be read-only to the optical disk drive (S315). The optical disk drive receiving the command sets itself read only (S321). Because only the BIOS sends the read-only command or a command to release it to the optical disk drive, the read-only setting cannot be released from an OS, another OS, or application software when control transfers to the OS. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technology for setting security for a storage device, and more particularly to a technology for prohibiting writing from a computer to a writable storage device.

  An optical disc is a generic name for a disk-shaped storage medium that reads and writes data using laser light. Among optical discs, CDs and DVDs are commonly used at present, but next-generation standard discs such as Blu-ray Disc (hereinafter referred to as BD) and HD-DVD are also put on the market. Has begun. These optical discs are used not only as data media for storing computer data, but also as media for recording and reproducing music and video with a dedicated device. An optical drive is a storage device that reads and writes data by rotating an optical disk. In personal computers (hereinafter referred to as PCs), an optical drive is mounted on the majority of products regardless of the type such as a desktop type or a notebook type.

  Optical disks have similar external shapes, but are manufactured according to various different standards and often cause user confusion during use. Even in the case of a data medium, each of CD, DVD, BD, and HD-DVD has a classification such as a read-only one, a one-time writable one, or a plurality of rewrites. There are many types of optical drives to meet these many standards. Typical types of optical drives include a CD-ROM drive that can only read from a CD, a DVD-ROM drive that can read from a CD and a DVD, a read / write from a CD, and a read from a DVD. There are possible combo drives, super-multi drives that can read and write to all CDs and DVDs, and so on. In particular, recently, an optical drive capable of writing data, such as a combo drive and a super multi drive, has been widely used. If the next generation standards such as BD and HD-DVD are included in this, the types of optical drives are further increased.

As a technique for operating a storage device capable of reading and writing so that only reading from a computer is possible, there are the following techniques. Japanese Patent Laid-Open No. 2004-26883 uses the BIOS by confirming permission / non-permission of use of the storage device set by the administrator during the computer startup process and prohibiting initialization of the storage device based on the confirmed conditions. It is a limitation. Also described is a technique for restricting writing to a storage device using a filter driver during control by an operating system (hereinafter referred to as OS). Japanese Patent Application Laid-Open No. 2004-228561 describes a technique for providing a write protect device between a computer and a magnetic disk device to prohibit writing to the magnetic disk device. Patent Document 3 describes a disk device that switches between a writable mode and a non-writable mode by an external switch operation. Japanese Patent Application Laid-Open No. 2004-228688 describes a technique for suppressing the recording function of an optical disc apparatus that can be originally recorded and erasing only by erasing a part of the flash memory by firmware processing.
JP 2006-309296 A JP 2004-47041 A JP 2002-251324 A JP 2007-12123 A

  As described above, optical drives that can read and write data (hereinafter referred to as writable) have become widespread. As a result, optical drive manufacturers can only read data in order to reduce the number of parts and products and reduce costs. There is a tendency to limit the production of possible read-only (hereinafter read-only) optical drives. As a result, only writable optical drives have been introduced to the market, making it difficult to obtain read-only optical drives.

  Further, as described above, there are many types of optical drives in order to cope with optical discs of various standards. As new standard optical discs appear, the types of optical drives increase. A PC manufacturer needs to reduce the number of parts held for manufacturing and maintenance as much as possible to simplify parts management and reduce costs. For this reason, many PC manufacturers are trying to stop holding read-only optical drives as parts.

  However, this does not mean that such a read-only optical drive is no longer necessary. Users such as corporations and public institutions are strengthening security management so as not to leak a large amount of personal information and confidential information handled in business. One of information leakage routes is that a recording medium on which data is written by a writable storage device is removed from the PC and taken out to the outside. For this reason, those users specially order a PC, such as an optical drive, in which the recording medium alone or the recording medium and the storage device are integrated into a read-only storage device that is removable from the PC. Sometimes. As a PC manufacturer, it is necessary to supply a PC equipped with a read-only storage device in order to meet such demand.

  In order to cope with this problem, it is conceivable that a writable optical drive is attached to a PC and set in advance to be read-only before shipment. The technology of Patent Document 1 is that the optical drive is practically limited by a device driver that restricts a write command sent from a PC under the control of the OS to a writable optical drive that cannot be set to read-only. To be read-only. However, even in application software that runs on an OS such as Windows (registered trademark), data access to the optical drive directly from the application software does not go through the device driver provided by the OS to the application software. There is something to do. In such a case, even if the technique of Patent Document 1 is adopted, there is a risk that a write command is sent directly from the application software to the optical drive without going through the device driver.

  Further, by using a floppy (registered trademark) disk, CD-ROM, external hard disk drive (hereinafter referred to as HDD), etc., it is different from the OS that is normally installed in the internal HDD on the same PC. It is also possible to install and start the OS. On the other hand, when the technique of Patent Document 1 is applied, another device driver included in another OS different from the device driver configured to prevent the transmission of the write command is started, so the write command Transmission of is not limited.

  On the other hand, the optical drive according to the technique of Patent Document 4 is set so that the recording function of the originally writable optical drive is stopped and the read-only operation is performed. When this optical drive is mounted on a PC, the OS normally sends a command for setting the read only to the optical drive, and the optical drive executes the command and operates so as to be read only. . However, even in this case, there is a possibility that a command for canceling the read-only operation may be sent from the application software that can directly access the optical drive without going through the device driver. In addition, when another unscheduled OS is installed and started, the read-only command is not sent to the optical drive or the release command is sent, ensuring read-only operation. Is not expected.

  In addition, when the optical drive that can be set to read only that was originally installed in the PC was removed, and instead a writable optical drive that cannot be set to read only was installed, the optical drive was sent from the OS. Since the command to set to read-only is not executed, the read-only operation is not ensured. In particular, many recent PCs are provided with a swappable bay in which peripheral devices such as an optical drive can be attached, removed, or replaced while the OS is operating after the power is turned on. If the optical drive is detachably connected to the PC via a swappable bay, the optical drive can be easily replaced, so there is a high risk that a writable optical drive that cannot be set to read-only will be installed in an operable state. .

  With the conventional method as described above, it is impossible to ensure security even if a writable optical drive is operated in a read-only manner. From the viewpoint of preventing information leakage, it is possible to make it impossible to attach the optical drive to the PC or to disable the interface used to connect the optical drive to the PC. Since installation of legitimate application software to be used and browsing of data are also restricted, convenience for users is impaired. The same problem exists not only in optical drives but also in most of storage devices that can be attached to and detached from a PC, such as hard disk drives or semiconductor storage devices.

  Accordingly, an object of the present invention is to provide a method for a computer to securely set security for a readable and writable storage device. A further object of the present invention is to provide a computer capable of such security settings. A further object of the present invention is to provide a computer program (BIOS) that causes a computer to perform such settings.

  According to a first aspect of the present invention, there is provided a method for a computer to set security for a storage device that can be read and written. In this setting method, the computer executes the BIOS to check whether the storage device has a security function. The security function means a function for the storage device to operate according to the security setting processing according to the present invention. For example, when the storage device receives a specific command from the computer, the storage device makes itself read-only, It can be set as the function which cancels | releases. When the storage device has a security function, the BIOS sets security for the storage device. And even if the setting by the BIOS is maintained and the control shifts to the OS, security for the storage device is ensured.

  In the present invention, since the security setting for the storage device is performed only by the BIOS, the security setting once set is canceled by accessing the storage device directly from the application software or by starting another OS. I can't. The BIOS can be replaced only by the computer manufacturer, can be replaced only by an administrator who knows the supervisor password, or the computer cannot be operated when it is replaced together with the non-volatile memory. Therefore, it is difficult for a general user to release the security set for the storage device. If the security setting is performed at the timing when POST is executed after the computer is turned on, the security of the storage device is ensured every time the computer is started.

  If the storage device does not execute a specific command related to the security setting after a predetermined time has elapsed after receiving the initialization command during execution of POST, the specific command The risk of being stolen and unlocking security can be reduced. When the BIOS acquires specific information of the storage device and encrypts a specific command related to security using the specific information, the specific command is intercepted in the process of being transferred from the computer to the storage device, or the storage device is disassembled. Or the possibility of being stolen.

  The computer can prepare in advance setting information including a setting for completely restricting access to the storage device, a setting for making access unlimited, and a setting for making the storage device read-only. The BIOS can flexibly select a security setting method for the storage device by using the setting information. For example, if the storage device has a security function, the BIOS can disable the input / output port of the computer for the storage device, make the storage device read-only, or allow access freely based on the setting information become. When the storage device does not have a security function, the BIOS can invalidate the input / output port for the storage device of the computer or freely set access based on the setting information.

  According to a second aspect of the present invention, there is provided a security setting method when a storage device is connected to a computer while the computer is executing an OS. When it is detected that a storage device is connected to the computer during execution of the OS, control is transferred from the OS to the BIOS. Then, the BIOS sets the storage device to read-only, and shifts the control from the BIOS to the OS while maintaining the state set to read-only, whereby secure security setting by the BIOS can be realized.

  According to a third aspect of the present invention, there is provided a computer that can be read and written and can be equipped with a storage device having a security function. This computer has a recording medium for storing an OS, a nonvolatile memory for storing a BIOS, a processor capable of switching between the OS and the BIOS, a connection unit for connecting the storage device, and security setting information for the storage device And a storage unit for storing. If it is determined that the storage device connected to the connection unit has a security function, the processor executes the BIOS to set the storage device to read-only. This storage device can be any one of an optical drive, a hard disk drive, and a semiconductor storage device. In addition, the connection unit can connect the storage device to the computer via any interface standard among IDE, USB, PCMCIA, CardBus, miniPCI, and Express Card.

  In the present invention, the drive unit of the storage device is connected to the computer by a connector or optical communication and physically removed from the computer together with the recording medium, or the storage device itself is fixed to the computer and only the recording medium is removed from the storage device. Especially suitable for cases. In addition, when it is detected that the storage device is connected to the connection unit while the OS is running, the processor receives the SMI, and shifts control from the OS to the BIOS to set the storage device to read-only. it can. As a result, the storage device connected by hot swap while the OS is operating can also be set to read-only operation. Further, according to a fourth aspect of the present invention, there is provided a BIOS for realizing a function for performing the above-described security setting on a computer.

  According to the present invention, it is possible to provide a method for a computer to securely set security for a readable / writable storage device. Furthermore, according to the present invention, it is possible to provide a computer capable of such security settings. Furthermore, according to the present invention, it is possible to provide a computer program (BIOS) that allows a computer to perform such settings.

  FIG. 1 is a perspective view showing the appearance and configuration of a notebook PC (hereinafter referred to as a notebook PC) 10 according to an embodiment of the present invention. The notebook PC 10 includes a casing 11 having a keyboard and a pointing device mounted on the surface and housing many devices therein, and a lid 13 having a liquid crystal display (LCD) mounted on the surface. An optical drive 21 is attached to the side surface of the housing 11. The optical drive 21 has a tray 23 that opens and closes, and an eject button 25 is attached to the tray 23 so as to be exposed on the side surface of the casing 11 at all times. When the user presses the eject button 25, the tray 23 protrudes to the side surface of the housing 11. In the optical drive 21, a spindle 29 and a pickup 31 are attached to the tray 23 side from the viewpoint of saving space. When the user inserts and sets the center of the optical disk 27 on the spindle 29 on the tray 23 and pushes the tray 23 protruding from the side surface of the casing 11 back into the casing 11, the spindle 29 rotates and the pickup 31 reciprocates in the direction from the center to the periphery of the optical disk 27, whereby the optical drive 21 can read and write data from and to the optical disk 27.

  The optical drive 21 is attached to the notebook PC 10 via a swappable bay. This swappable bay is a hot swap that installs, removes, and replaces devices while the OS is running on the notebook PC 10, and a warm that mounts, removes, and replaces devices while the notebook PC 10 is suspended.・ Supports swap. The optical drive 21 can be removed from the notebook PC 10 by moving the detachable lever 33 of the swappable bay. The detachable lever 33 is a lever that physically separates the optical drive 21 from the interface, and at the same time, recognizes an operation for attaching the optical drive 21 and an operation for attempting to disconnect the optical drive 21 and processes software corresponding to those operations. It includes a switch (not shown) for enabling

  FIG. 2 is a block diagram illustrating a schematic configuration of hardware of the notebook PC 10. The CPU 101 is an arithmetic processing unit that has a central function of the notebook PC 10 and executes an OS, a BIOS, a device driver, an application program, or the like. The CPU 101 can operate in an SMM (System Management Mode) which is a privileged execution mode for system management when an SMI (System Management Interrupt) input pin (SMI #) is asserted. The CPU 101 operating in the SMM can mainly execute suspend, resume, power management, and security-related operations under the control of the BIOS.

  The CPU bridge 103 includes a memory controller function for controlling an access operation to the main memory 105 and a data buffer function for absorbing a difference in data transfer speed between connected devices. Yes. The main memory 105 is a writable memory used as a reading area for a program executed by the CPU 101 and a work area for writing processing data. At the same time, the main memory 105 includes an area as SMRAM (System Management RAM), which will be described later. The video card 107 has a video chip (not shown) and a VRAM (not shown), generates an image to be drawn in response to a drawing command from the CPU 101, writes the image to the VRAM, and reads the image read from the VRAM. It is sent to the display 109 as drawing data.

  The I / O bridge 111 is a device controller that constitutes a chip set in the same manner as the CPU bridge 103. The I / O bridge 111 includes an IDE port 113 having an IDE (Integrated Device Electronics) interface function. Further, the I / O bridge 111 can connect various peripheral devices compliant with the USB standard via the USB interface 115. The various peripheral devices referred to here include storage devices such as an external optical drive, a hard disk drive, and a semiconductor storage device. Furthermore, it is possible to connect storage devices corresponding to the respective standards through the CardBus interface 117 and the miniPCI interface 119.

  The IDE port 113 is connected to an HDD 121 compatible with ATA (Advanced Technology Attachment) or serial ATA, and an optical drive 21 compatible with ATAPI (ATA Packet Interface). In the HDD 121, an OS, a device driver, an application program, and the like are installed. The optical drive 21 is connected to the IDE port 113 via the swappable bay 123. The swappable bay 123 includes a lever switch 125 that opens and closes when the user moves the attachment / detachment lever 33 in order to attach / detach the device to / from the device. Details thereof will be described later.

  Further, the I / O bridge 111 is connected to a device that does not require high-speed data transfer via the LPC bus 127. A BIOS flash ROM 129, a secure NVRAM (Non-Volatile RAM) 131, and an embedded controller 133 are connected to the LPC bus 127. The BIOS flash ROM 129 and the secure NVRAM 131 will be described later.

  The embedded controller 133 is a microcomputer composed of an 8- to 16-bit CPU, ROM, RAM, etc., and further has an A / D input terminal, a D / A output terminal, a timer, and a digital input / output terminal for a plurality of channels. It has. A cooling fan (not shown), a temperature sensor (not shown), and a power controller (not shown) for controlling the power supply device are connected to the embedded controller 133 via their input / output terminals. Thus, a program related to management of the operating environment inside the PC can be executed independently of the CPU 101. The lever switch 125 of the swappable bay 123 is also connected to the embedded controller 133, and the embedded controller 133 recognizes that the device has been attached to or detached from the swappable bay 123 by recognizing the opening / closing of the lever switch 125. . Further, the embedded controller 133 can operate with the SMM by asserting the SMI # of the CPU 101, and can manage the supply of power to the devices connected to the swappable bay 123.

  Note that FIG. 2 is merely a simplified description of the hardware configuration and connection relationships necessary to explain the present embodiment. In addition to those mentioned above, there are many devices for configuring the PC 10 such as a wired LAN adapter, a wireless LAN module, a power supply device, an I / O controller, an input / output device such as a keyboard and a mouse. used. However, they are well known to those skilled in the art and need not be described in detail here because they do not require a specific explanation for understanding the present invention. Of course, a person skilled in the art may arbitrarily configure the plurality of blocks described in FIG. 2 as one integrated circuit or device, or conversely divide one block into a plurality of integrated circuits or devices. The range that can be selected is included in the scope of the present invention.

  FIG. 3 is a block diagram showing a schematic configuration inside the optical drive 21. Inside the optical drive 21, an MPU (Micro Processing Unit) 201 executes firmware 205 stored in the flash ROM 203 to control all functions of the optical drive 21. More specifically, the MPU 201 moves the pickup 31 on the optical disk 27 by moving the host interface 209 that communicates with the IDE port 113, the rotation control system 211 that controls the rotation of the spindle motor 219, and the coarse motor 221. The coarse movement control system 213 that moves near the target track of the optical disk 27, the pickup control system 215 that controls the actuator (not shown) on the pickup 31 to irradiate the target track on the optical disk 27, and the pickup 31 is optical. Each function such as a signal processing system 217 for processing a signal read from the disk 27 to reproduce data and generating a signal to be recorded on the optical disk 27 based on data sent from the host interface 209 is controlled.

  The flash ROM 203 also records a device ID 206 unique to the optical drive 21 and an R / O status bit 207 indicating whether the read only (R / O) setting of the optical drive 21 is valid or invalid. The optical drive 21 is writable, but if the read-only setting is recorded in the R / O status bit 207 as valid, the firmware 205 operates the optical drive 21 as being read-only. In the optical drive 21, when the host interface 209 receives a read-only setting command from the IDE port 113, the R / O status bit 207 can be rewritten and the operation of the firmware 205 can be set to read-only. Similarly, when the host interface 209 receives a read-only release command from the IDE port 113, the optical drive 21 can rewrite the R / O state bit 207 and set the operation of the firmware 205 to be writable. . Such a read-only or writable setting is called a security function of the optical drive 21. The firmware 205 includes a timer function. The read-only setting command and the read-only release command are accepted only for a certain period of time after the optical drive 21 is turned on and receives an initialization command by the timer function included in the firmware 205. The state of the R / O state bit 207 is maintained even when the optical drive 21 is turned off. Details of these will be described later.

  FIG. 4 is a diagram showing an internal configuration of the BIOS flash ROM 129, the secure NVRAM 131, and the main memory 105. The BIOS flash ROM 129 shown in FIG. 4A is a non-volatile memory in which stored contents can be electrically rewritten. The system BIOS 251, which is a basic program used for system startup and management, power supply, temperature, etc. Various utilities 253, which are software for managing the operating environment, are activated when the power of the notebook PC 10 is turned on, and POST (Power-On Self Test) 255 that performs initial setting and testing of hardware, and the CPU 101 operates in SMM. The SMI service routine 257 that is sometimes activated, the INT13H handler 259 that accesses the HDD 121, and the like are stored. These program modules stored in the BIOS-ROM 129 constitute a BIOS. In the present embodiment, the POST 255 is configured to perform an operation of setting the optical drive 21 to read-only. The program module to be set to read only can be configured separately from the POST 255. Further, when the CPU 101 shifts from the control by the OS to the SMM, the SMI service routine 257 performs the operation of setting the optical drive 21 to read only. Details of both will be described later.

  The secure NVRAM 131 shown in FIG. 4B is a RAM that is backed up by a battery so that it does not disappear even when the notebook PC 10 is turned off, and the stored contents can be set to read / write prohibition by an operation by the system BIOS 251. The secure NVRAM 131 stores setting information 261 of a PC device controller (CPU bridge 103 and I / O bridge 111) and device information 263 that is information about each device connected to the device controller. The contents of the setting information 261 mainly include the startup sequence and drive number of the disk device, the connection method of each peripheral device, parameters related to data transfer, and a POP (power-on password). The device information 263 includes a device ID 206 unique to each device connected to the device controller, setting information inside each device, and the like. The device ID 206 and internal setting information of the optical drive 21 connected to the swappable bay 123 are also included in the device information 263.

The setting information 261 concerning the optical drive 21 connected to the IDE port 113 shows the following three types (1) to (3).
(1) “HIGH”
Regardless of whether the optical drive 21 has a security function or not, disabling the IDE port 113 for the optical drive 21 prevents the notebook PC 10 from recognizing the presence of the optical drive and completely restricts access.
(2) “R / O”
When an optical drive 21 having a security function is connected to the IDE port 113, the optical drive 21 is set to read-only. When an optical drive that does not have a security function is connected, the IDE port 113 is disabled as in the case of “HIGH”.
(3) “NONE”
Access from the notebook PC 10 to the optical drive 21 connected to the IDE port 113 is freely performed without restriction. When the optical drive 21 set to read only is mounted, it is set to writable.
The notebook PC 10 can incorporate any of the above settings (1) to (3) at the stage of assembly at the factory based on the user's application, but in this embodiment, the state set in (2) is used. The explanation will be centered. The setting contents are stored in the secure NVRAM so that only the BIOS can be accessed.

  In the main memory 105 shown in FIG. 4C, an area as an SMRAM (System Management RAM) 271 is secured in addition to the user area 273 used in the normal operation of the notebook PC 10. When the SMI # of the CPU 101 is asserted by the hardware, the CPU 101 enters the SMM operation, and the SMI service routine 257 is called and executed under the control of the system BIOS 251. Since the CPU 101 operating in the SMM is a single task operation, all interrupts are disabled, and the SMRAM 271 can be used exclusively by the CPU 101 operating in the SMM, so that tasks other than the SMI service routine 257 can be controlled. Never cross. While the CPU 101 operates in the SMM, the operating state of the OS and the software and user data operating on the OS and immediately before the transition to the SMM is held in the user area 273. Information indicating the state of the register immediately before the transition to the SMM is stored in the SMRAM 271. When the CPU 101 ends the operation in the SMM, the CPU 101 shifts to the control by the OS based on the information indicating the register state stored in the SMRAM 271 and restores the operation state held in the user area 273.

  FIG. 5 is a flowchart illustrating the processing executed when the optical drive 21 is attached to the notebook PC 10 described above and the power is turned on. When the notebook PC 10 is powered on, the hardware initialization process is started by the POST 255 under the control of the system BIOS 251 (blocks 301 to 303). The POST 255 sends an initialization command to the optical drive 21 (block 305). In the initialization command, the POST 255 has a device ID 206 of the optical drive 21 and a security function for causing the optical drive 21 to operate as a read-only device and to release it. Queries whether it is compatible or not. The inquiry about the security function is made by a vendor command that can be set and used independently by the manufacturer in the IDE command. Accordingly, since the optical drive 21 that does not support the security function does not respond to the vendor command, the POST 255 can determine that the optical drive 21 does not support the security function if there is no response to the transmitted command. Of course, this vendor command is not open to the public.

  Upon receiving the initialization command (block 307), the optical drive 21 returns its own device ID 206 and the presence or absence of the security function to the POST 255 (block 309). Based on the response from the optical drive 21, the POST 255 first determines whether or not the optical drive 21 has a security function (block 311). If the optical drive 21 is compatible with the security function, the setting related to the optical drive 21 included in the setting information 261 is confirmed (block 313). If the confirmed setting is “R / O”, the POST 255 transmits a command for setting the optical drive 21 to read-only (hereinafter referred to as a read-only setting command) (block 315). If the confirmed setting is “NONE”, the POST 255 transmits a command to release the read-only of the optical drive 21 (hereinafter referred to as a read-only release command) (block 317). If the confirmed setting is “HIGH”, the POST 255 invalidates the connection portion of the IDE port 113 to the optical drive 21 (block 319), and proceeds to the processing of block 331.

  Upon receiving the read-only setting command, the optical drive 21 sets itself to a read-only operation (block 321). The optical drive 21 that has received the read-only release command cancels its own read-only setting so that it can operate writable (block 323). Note that the read-only setting command and the read-only release command are also vendor commands that are not generally disclosed. In blocks 315 and 317, if the read-only setting command and the read-only release command are encrypted using the device ID 206 received by the POST 255 as a key and transmitted, the optical drive 21 can be analyzed or the optical drive from the notebook PC 10 can be analyzed. This is more preferable because it is difficult to analyze the command sent to the terminal 21 and to determine a method for canceling the read-only setting. The optical drive 21 in which the read-only setting or release has been completed returns a reply that the command has been normally completed to the POST 255 (block 325). The POST 255 determines whether or not a reply indicating that the command has been normally completed is received from the optical drive 21 (block 327). If the reply is normal, the process proceeds to block 331. Then, after invalidating the connection portion of the IDE port 113 to the optical drive 21, the process proceeds to block 331.

  Even when it is determined in block 311 that the optical drive 21 does not correspond to the security function, the setting related to the optical drive 21 included in the setting information 261 is confirmed (block 329). If the confirmed setting is “R / O” or “HIGH”, the POST 255 proceeds to block 319, invalidates the connection portion of the IDE port 113 to the optical drive 21, and then proceeds to the processing of block 331. If the confirmed setting is “NONE”, the POST 255 proceeds to the processing of block 331. The POST 255 that has completed the above processing stores the device ID 206 related to the optical drive 21 and the presence / absence of the security function determined in the block 311 as the device information 263 in the secure NVRAM 131 (block 331) to prohibit subsequent access. The secure NVRAM 131 is locked. Thereafter, the INT 13H handler 259 is called from the BIOS-ROM 129 to activate the OS (blocks 333 to 335). The processing relating to the security setting of the optical drive 21 described with reference to FIG. 5 may be executed at any timing in the process from when the notebook PC 10 is powered on until the OS is started.

  FIG. 6 is a flowchart illustrating processing executed by the firmware 205 when the optical drive 21 receives a command from the IDE port 113. This flowchart shows a case where the optical drive 21 has a security function according to the present invention. When the optical drive 21 receives any command from the IDE port 113 (blocks 401 to 403), the firmware 205 first determines whether or not the command is a write command (block 405). If it is a write command, the firmware 205 then reads the R / O status bit 207 and determines whether it is a read-only setting (block 407). If the setting is not read-only, the optical drive 21 operates as a writable one, so the write command is executed as it is and a normal response is returned to the IDE port 113 (block 409). If the read-only setting is set, the optical drive 21 operates as a read-only device, so that the write command is not executed and an error is returned to the IDE port 113 (block 411).

  If the received command is not a write command at block 405, then the firmware 205 determines whether the command is an initialization command from the BIOS sent at block 305 of FIG. 5 (block 413). If it is an initialization command, the timer function is reset in the firmware 205 to start timing (block 415), and the process proceeds to block 409 to return a normal response to the IDE port 113. The normal response here includes its own device ID 206 and information on the presence or absence of a security function, as indicated by blocks 309 and 311 in FIG.

  If the received command is not an initialization command at block 413, then the firmware 205 determines whether the command is a read-only setting command or a read-only release command (block 417). If the command is not a read-only setting command or a read-only release command, the process proceeds to block 409 to execute the command and return a normal response to the IDE port 113. If it is a read-only setting command or a read-only release command, it is determined whether or not the timer function of the firmware 205 indicates that the elapsed time since the initialization command was received in block 415 is within a predetermined value. (Block 419). If a predetermined time or more has elapsed since the initialization command was received, the process proceeds to block 411, and an error is returned to the IDE port 113 without executing the command. If the elapsed time after receiving the initialization command is within a predetermined value, the process proceeds to block 409 to execute a read-only setting command or a read-only release command to rewrite the state of the R / O status bit 207, and the IDE port A normal response is returned to 113. The above processing ends when the optical drive 21 is turned off (blocks 421 to 423), but is repeated between the blocks 403 to 421 while the operation of the optical drive 21 continues.

  The maximum value of the elapsed time that is a criterion for the determination in block 419 can be set assuming a standard required time from when the notebook PC 10 is turned on until the processing of FIG. 5 ends. In short, the elapsed time is set so that the read-only setting command or the read-only release command sent to the optical drive 21 is accepted only while the notebook PC 10 is executing the processing of FIG. The maximum value can be set. In this way, when the OS is activated in the notebook PC 10 via the processes shown in FIGS. 5 and 6, even if a security-related command is stolen, the read-only setting is canceled via the OS. It is safe because it cannot. In addition, in order to be able to cancel the read-only only when the optical drive 21 is controlled by the BIOS, for example, once the read-only setting command is received, the read / write until the optical drive 21 is turned off. There is also a method of not accepting only release commands. Alternatively, there is a method in which a bit indicating whether or not a read-only setting command or a read-only release command has already been received is provided in the flash ROM 203 separately from the R / O status bit 207.

  If the setting related to the optical drive 21 included in the setting information 261 is “R / O”, the OS started after the optical drive 21 is set to read-only by the processing described above is executed by the optical drive 21. Is recognized as being read-only. Accordingly, a write command is not sent to the optical drive 21 via a device driver that controls input / output of data from the OS to the optical drive 21. Even if there is application software that sends a write command to the optical drive 21 without going through the OS device driver, the command is processed by the internal processing of the optical drive 21 set to read-only as in block 411. An error is returned.

  Furthermore, since the operation of setting the optical drive 21 to read-only is performed at the initial setting stage under the control of the BIOS before the OS is started, another OS different from the OS that is normally installed in the notebook PC 10 is used. Even if the OS is started, the optical drive 21 is already set to read-only when the OS is started. If the time set by the timer elapses, the encrypted correct command is sent by the OS. Even if it is done, the read-only setting cannot be cancelled. In addition, even when an optical drive that does not have a security function that can be set to read-only is connected and the notebook PC 10 is turned on, if the setting information of the secure NVRAM 131 is “R / O”, the IDE port By disabling the connection to the optical drive, the optical drive becomes unusable and safe. When the setting information of the secure NVRAM 131 is “R / O”, only the optical drive 21 having the security function according to the present invention can be used after being set to read only.

  However, the optical drive 21 is connected to the notebook PC 10 via the swappable bay 123. Therefore, if the notebook PC 10 is activated with the optical drive 21 removed from the swappable bay 123, the OS can be activated without performing the operation of setting the optical drive 21 to read-only. Then, it is desirable in terms of security if the optical drive 21 is connected to the swappable bay 123 by hot swap after the OS is started so that the optical drive 21 can be operated in a writable state without the operation of setting to read only. Absent. In addition, by connecting an optical drive that does not have a security function that can be set to read-only from the beginning by hot swapping, security is sufficient so that the optical drive can be used without invalidating the operation of the IDE port. It cannot be said that it has been secured.

  FIG. 7 is a flowchart illustrating processing executed when the optical drive 21 is connected to the swappable bay 123 of the notebook PC 10 in which the OS is activated by hot swapping. When the optical drive 21 is attached to the swappable bay 123 (block 501), the detachable lever 33 is always moved, so that the embedded controller 133 recognizes that the lever switch 125 is opened and closed (block 503). The embedded controller 133 responding to the opening / closing of the lever switch 125 asserts the SMI # of the CPU 101 to operate in the SMM (block 505), and expands and executes the SMI service routine 257 in the SMRAM 271 under the control of the system BIOS 251. Let Since the operation of the embedded controller 133 is independent of the CPU 101, the above processing is performed without depending on the OS. Further, unlike the processing by POST 255 that requires initialization for the entire hardware, the processing by the SMI service routine 257 need only perform processing related to the device connected to the swappable bay 123.

  The SMI service routine 257 sends a device initialization command to the optical drive 21 in the same manner as the processing block 305 by the POST 255 shown in FIG. 5 (block 507). In the device initialization command, the SMI service routine 257 inquires the optical drive 21 about the device ID 206 of the optical drive 21 and the presence or absence of the security function of the optical drive 21. Upon receiving the initialization command, the optical drive 21 returns the queried content to the SMI service routine 257 in the same manner as the operation described in blocks 307 to 309.

  The SMI service routine 257 that has received the reply (block 509) first determines whether the optical drive 21 has a security function (block 511). If the optical drive 21 is compatible with the security function, the SMI service routine 257 then sets the device ID 206 and security settings of the optical drive 21 and device information about the optical drive previously connected to the swappable bay 123. The information recorded as 263 is compared (block 513). If it is determined that the same optical drive 21 as the previous one is connected and the setting of whether or not read-only is the same as the previous one, the operation of the new setting may be omitted. Proceed to processing.

  If it is determined in block 513 that the same optical drive 21 as in the previous time has not been connected, or if it is determined that the setting as to whether it is read-only is different from the previous time, it is included in the setting information 261 The setting related to the optical drive 21 to be checked is confirmed (block 515). If the confirmed setting is “R / O”, the SMI service routine 257 sends a read-only setting command to the optical drive 21 (block 517). If the confirmed setting is “NONE”, the SMI service routine 257 sends a read-only release command to the optical drive 21 (block 519). If the confirmed setting is “HIGH”, the SMI service routine 257 disables the connection of the IDE port 113 to the optical drive 21 (block 521). It is determined whether or not the SMI service routine 257 has received a reply that the command has been normally completed from the optical drive 21 in which the setting or cancellation of the read-only operation has been completed in response to the commands of the blocks 517 and 519 ( Block 523), if normal, the process proceeds to block 527 as it is, and if a normal reply is not received, the process proceeds to block 521 to invalidate the connection portion of the IDE port 113 to the optical drive 21, and then proceeds to block 527 .

  If the optical drive 21 does not support the security function in block 511, the setting related to the optical drive 21 included in the setting information 261 is also confirmed in this case (block 525). If the confirmed setting is “R / O” or “HIGH”, the SMI service routine 257 proceeds to block 521 to invalidate the connection portion of the IDE port 113 to the optical drive 21, and then proceeds to the processing of block 527. move on. If the confirmed setting is “NONE”, the SMI service routine 257 proceeds to the processing of the block 527 as it is. The SMI service routine 257 having completed the above determination and processing stores the device ID 206 of the optical drive 21, the presence / absence of the security function, and the setting contents as device information 263 in the secure NVRAM 131 (block 527), and ends SMM. Then, the operation by the OS is resumed (blocks 529 to 531). The secure NVRAM 131 is locked by the POST 255 before shifting to control by the OS, and thereafter cannot be accessed from the OS or application software. When the operation by the OS is resumed, the newly connected optical drive 21 is recognized on the OS side, and processing such as reading of the corresponding device driver is performed.

  Even in the case of hot swap to the swappable bay 123, the optical drive 21 is connected to the swappable bay 123 and then an initialization command is transmitted in block 507. As shown in FIG. 6, the optical drive 21 can accept a read-only setting command or a read-only release command for a predetermined time after the initialization command is transmitted. After the fixed time has elapsed, the setting cannot be canceled by a command. That is, even in the case of hot swap to the swappable bay 123, security can be ensured by making the operation on the optical drive 21 side the same as that shown in FIG.

  Note that while the notebook PC 10 is in the suspended (or hibernation) state, the power supply to the optical drive 21 is stopped, but the content stored in the R / O state bit 207 is turned off. Is also retained. Accordingly, if the R / O status bit 207 is set to read-only before being suspended, the optical drive 21 operates again in a read-only manner even when the notebook PC 10 is resumed. The OS operating on the notebook PC 10 also resumes and operates as it is in the state before being suspended, including recognition and setting for the optical drive 21. Even when the optical drive 21 is once ready to accept a read-only release command when the notebook PC 10 resumes, the timer function inside the optical drive 21 passes a certain time when the OS operation resumes. Then, since the read-only release command is not accepted again, security is ensured.

  If the setting of the R / O status bit 207 is not retained when the optical drive 21 is turned off, the SMI service routine 257 is resumed when the notebook PC 10 is suspended and resumed and the optical drive 21 is turned on again. And the optical drive 21 may be set to read-only again. Also in this case, when the OS operation is resumed, the optical drive 21 does not accept a read-only setting or read-only release command by the timer function.

  All the operations described above are performed by hardware and BIOS (POST 255 and SMI service routine 257), and the OS and application software are not involved. Therefore, regardless of the type or setting of the OS, even if another OS that is different from the OS that is normally installed in the notebook PC 10 is started, the setting related to the optical drive 21 included in the setting information 261 is “ "R / O", the optical drive does not operate in a writable state. Further, not only when the optical drive 21 is attached to the notebook PC 10 and the power is turned on, but also when the optical drive 21 is hot swapped in the swappable bay 123, it does not have a security function that can be set to read only. Even when the optical drive is hot swapped, if the setting for the optical drive 21 included in the setting information 261 is “R / O”, the optical drive does not operate in a writable state.

  The example of the optical drive has been described above, but the present invention can also be applied to a writable storage device connected to a PC, such as a hard disk drive or a semiconductor storage device. The present invention is also applicable to an interface capable of connecting a writable storage device to a PC, such as IDE, USB, PCMCIA, CardBus, miniPCI, and ExpressCard. These storage devices may be either a case where the recording medium can be attached to and detached from the PC 10 alone, or a case where the storage medium can be attached and detached as a storage device in which the recording medium and the drive device are integrated. What is important in this case is that a write inhibit command is transmitted to the storage device when the BIOS is executed on the PC, the storage device is in a read-only operation in response to the write inhibit command by the BIOS, and the OS This means that the read-only operation of the storage device cannot be released while the memory device is operating. For storage devices that can be hot-swapped while the OS is operating, the hardware on the PC side can detect the connection of the storage device, regardless of the OS and application software. This is more desirable because the storage device can be set to read-only under the control of the BIOS.

  In the operation when the setting related to the optical drive 21 included in the setting information 261 described in FIGS. 5 and 7 is “HIGH”, the connection portion of the IDE port 113 to the optical drive 21 is invalidated ( Instead of the operations of blocks 319 and 521), an error may be returned without executing all the read and write commands sent from the IDE port 113 inside the optical drive 21. In that case, the optical drive 21 needs to be able to handle such an operation, and the POST 255 and SMI service routine 257 need to be able to send commands to operate the optical drive 21 in that way.

  In addition, the setting related to the optical drive 21 included in the setting information 261 needs to be something that the user cannot change without permission. In the above-described embodiment, this setting is incorporated at the stage of assembly at the factory, but this can be set by the administrator by using a supervisor password that can only be used by the administrator and cannot be used by the user. You may do it.

  Although the present invention has been described with the specific embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and is known so far as long as the effects of the present invention are achieved. It goes without saying that any configuration can be adopted.

  The present invention can be applied to a computer that uses a writable storage device that is detachably connected.

It is a perspective view which shows the external appearance of the notebook PC concerning embodiment of this invention. It is a block diagram which shows schematic structure of the hardware of the notebook PC concerning embodiment of this invention. It is a block diagram showing a schematic structure inside an optical drive concerning an embodiment of the invention. It is a figure which shows the internal structure of BIOS flash ROM, secure NVRAM, and main memory concerning embodiment of this invention. It is the flowchart which described the process performed when attaching an optical drive to notebook PC and turning on a power supply. It is the flowchart which described the process performed when an optical drive receives a command from an IDE port. It is the flowchart which described the process performed when connecting an optical drive by hot swap to the swappable bay of the notebook PC in which OS was started.

Explanation of symbols

10 ... Notebook PC
11 ... Case 21 ... Optical drive 33 ... Removable lever 101 ... CPU
111 ... I / O bridge 113 ... IDE port 123 ... swappable bay 125 ... lever switch 129 ... BIOS flash ROM
131 ... Secure NVRAM
133 ... Embedded controller 206 ... Device ID
207 ... R / O status bit 255 ... POST
257 ... SMI service routine 261 ... Setting information 263 ... Device information 271 ... SMRAM

Claims (18)

A method for a computer to set security for a readable and writable storage device,
Connecting the storage device to the computer;
The BIOS confirming the presence or absence of the security function of the storage device in a state where control by the operating system is not performed;
When the BIOS determines that the storage device has the security function, the BIOS sets security related to the storage device;
Transferring control from the BIOS to the operating system while maintaining the security settings.   The setting method according to claim 1, wherein the step of confirming the presence or absence of the security function and the step of setting the security are performed while the BIOS executes POST.   The setting according to claim 1, further comprising: a function for the storage device to set the security for itself and a function to cancel the security setting when the security function receives a specific command related to the security setting from the computer. Method.   The setting method according to claim 3, wherein the storage device does not execute the specific command received after a predetermined time has elapsed since the initialization command was received during POST.   The setting method according to claim 3, further comprising a step in which the BIOS acquires specific information of the storage device and a step of encrypting the specific command using the specific information.   2. The method comprising: providing the computer with setting information including a setting that completely restricts access to the storage device, a setting that restricts access to the storage device, and a setting that makes the storage device read-only. Setting method.   In the step of confirming the presence or absence of the security function, it is determined that the storage device has the security function, and when the setting information indicates a setting for completely restricting the access, the BIOS is set in the step of setting the security. The setting method according to claim 6, wherein an input / output port of the computer for the storage device is invalidated.   When it is determined that the storage device has the security function in the step of confirming the presence or absence of the security function, and the setting information indicates a setting to make the read only, the BIOS stores the storage in the step of setting the security. The setting method according to claim 6, wherein the apparatus is made read-only.   In the step of confirming the presence or absence of the security function, it is determined that the storage device has the security function, and when the setting information indicates a setting for restricting the access, the BIOS sets the security in the step of setting the security. The setting method according to claim 6, wherein access to the storage device from a computer is made free.   When the step of confirming the presence or absence of the security function determines that the storage device does not have the security function and the setting information indicates either the setting to make the read-only or the setting to completely restrict the access, 7. The setting method according to claim 6, wherein the BIOS invalidates an input / output port of the computer for the storage device in the step of setting the security.   The method according to claim 1, wherein the step of confirming the presence or absence of the security function is performed based on information sent from the storage device to the computer in response to an initialization command sent from the computer to the storage device. A method for a computer to set a storage device that is readable and writable and that can be set to read-only to read-only,
Running the operating system;
Detecting that the storage device is connected to the computer during execution of the operating system;
Transferring control from the operating system to the BIOS in response to the detecting step;
The BIOS setting the storage device to read-only;
And a step of transferring control from the BIOS to the operating system while maintaining the read-only state. A computer that can be equipped with a storage device that can be read and written and can be set to read-only from the outside,
A recording medium for storing an operating system;
A non-volatile memory for storing the BIOS;
A processor capable of switching and executing the operating system and the BIOS;
A connection unit for detachably connecting the storage device;
A storage unit for storing security setting information for the storage device;
The computer, when determining that the storage device connected to the connection unit has a security function, executes the BIOS to set the storage device to read-only.   The computer according to claim 13, wherein the storage device is one of an optical drive, a hard disk drive, and a semiconductor storage device.   The computer according to claim 13, wherein the connection unit connects the storage device to the computer through an interface standard of IDE, USB, PCMCIA, CardBus, miniPCI, or Express Card.   14. The computer according to claim 13, wherein the storage device is configured such that a recording medium and a drive unit are integrated and removable from the computer, or the recording medium is configured to be removable from the drive unit.   A detection unit that detects that the storage device is connected to the connection unit while executing the operating system, and the processor detects the connection of the storage device when the detection unit detects connection of the storage device; 14. The computer according to claim 13, wherein control is transferred from the operating system to the BIOS to set the storage device to read-only. To a computer connected to a storage device that can be read and written and can be set to read-only,
A function for confirming whether or not the storage device can be set to read-only;
A function for referring to security setting information relating to the storage device;
A BIOS that realizes a function of setting the storage device to read-only based on the setting information while the operating system is not operating when it is determined that the storage device can be set to read-only. .

Images